1. Field of the Invention
The present invention relates to an apparatus and a method for processing a digital document and a computer program and, in particular, to an apparatus and a method for processing a digital document and a computer program that are suitable for processing a digital document stored in the apparatus.
2. Description of the Related Art
In recent years, multi-function printers (MFPs) have been able to store documents therein in a digital form in addition to copying documents and printing data written in page description language (PDL). Examples of such stored digital documents include documents scanned by a scanner and documents transmitted from a host computer in a PDL format. In addition, some MFPs can analyze the page description language so as to separate page data into image components. By storing the digital document on an image-component basis, MFPs can allow users to edit the digital document on an image-component basis and reuse the document (refer to, for example, Japanese Patent Laid-Open No. 10-208020).
Furthermore, some MFPs allow users to download a functional program in order to replace an old one with the new one. A software development kit (SDK) for developing a program that uses a function of an MFP is provided to users. Manufacturers, sales companies, and third parties can develop their own application programs using the SDK. Users can purchase these application programs to download the application programs into MFPs. In this way, the users can use functions that are not offered originally or that have improved operability (refer to, for example, Japanese Patent Laid-Open No. 2003-256216).
By using such a technology, users can develop an application program for editing and manipulating digital documents stored in MFPs. The users who use MFPs having such a function purchase a preferred edit application program and download the purchased edit application program into the MFPs so as to use the application program.
On the other hand, documents and images fall into two categories: those that can be freely edited and used and those that cannot be freely used due to copyright restrictions. Accordingly, documents that do not allow free use need to have a security setting in order not to be edited. For this purpose, a technology has been developed in which a function relating to an edit operation is automatically restricted so that users do not need to examine a security setting on an image basis when the users try to edit the document. Thus, the users are prevented from unintentionally editing the document and the images. In addition, a technology has been developed in which more precise control is performed by attaching edit-function level information that indicates an edit security level to each of the images (refer to, for example, Japanese Patent Laid-Open No. 2001-117687).